Compressing Light: Reflection in Small Gaps

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Discussion Overview

The discussion revolves around the behavior of photons being reflected between two horizontal sheets in a gap smaller than the wavelength of the light. Participants explore the implications of this scenario, particularly in relation to concepts such as cavity radiation and wave propagation in constrained spaces.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions what occurs when the distance between reflecting surfaces is smaller than the wavelength of the photon, suggesting a scenario of reflection.
  • Another participant asserts that nothing special happens with radio waves when reflected, implying a distinction based on wavelength.
  • A different participant introduces the concept of cavity radiation, stating that the size of the cavity limits the possible wavelengths of radiation within it.
  • Some participants note that reflection off a single reflector differs from the scenario described, emphasizing the role of cavity radiation and its restrictions on wavelength.
  • One participant mentions that while propagating modes cannot exist in a waveguide that is too narrow, non-propagating solutions may still be possible, citing the example of a parallel-plate capacitor in a quasistatic regime.

Areas of Agreement / Disagreement

Participants express differing views on the implications of reflecting light in small gaps, with some agreeing on the relevance of cavity radiation while others focus on the behavior of specific wavelengths like radio waves. The discussion remains unresolved regarding the exact nature of light behavior in this context.

Contextual Notes

The discussion includes assumptions about the nature of light and the definitions of cavity radiation, as well as the conditions under which different types of wave propagation may occur. There are unresolved aspects regarding the mathematical treatment of the scenarios presented.

Elbraido
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TL;DR
What happens when light doesn't have the space to complete a cycle?
Hi thereLet’s consider a photon of wavelength λ is being reflected across of gap d meters. The photon is a reflected back and forth between the same points on two horizontal sheets that reflect 100% of the light. What happens when the distance is smaller than wavelength?

Thanks
 
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Elbraido said:
Summary:: What happens when light doesn't have the space to complete a cycle?

Hi thereLet’s consider a photon of wavelength λ is being reflected across of gap d meters. The photon is a reflected back and forth between the same points on two horizontal sheets that reflect 100% of the light. What happens when the distance is smaller than wavelength?

Thanks
Radio waves have a long wavelength. Nothing special happens when they get reflected.

https://en.wikipedia.org/wiki/Radio_wave
 
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Elbraido said:
What happens when the distance is smaller than wavelength?

It can't be. What you are describing is cavity radiation. The size of the cavity restricts the possible wavelengths of the radiation inside it.
 
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PeroK said:
Radio waves have a long wavelength. Nothing special happens when they get reflected.

Reflection off a single reflector is not what the OP is describing. He is describing what amounts to cavity radiation. There are restrictions on the wavelength of cavity radiation.
 
PeterDonis said:
It can't be. What you are describing is cavity radiation. The size of the cavity restricts the possible wavelengths of the radiation inside it.

I guess it depends on how pedantic you want to be. You will have no propagting modes in a waveguide that is too 'narrow'. But non-propagating solutions can exist. Parallel-plate capacitor deep in quasistatic regime is an example that comes to mind.
 

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